Improvement in ordnance



T. A. BLA KELY.

Ordnance.

Patented Feb. 16, 1864 Witnzsses.

N.PETERS. PHOTO-LrmnGRAPNER. vnsmNGToN, o CA UNITED STATES PATENTOEEICE.N

THEOPHILUS A. BLAKELY, OE LONDON, ENGLAND.

IMPROVEMENT IN ORDNANCE.

Specification forming part of Letters Patent No. 4 1,662, dated FebruaryIG, 1864` To all whom t may concern:

Be it known that I, THEorHrLUs ALEXAN- DE a BLAKELY, of MontpelierSquare London, England, late captain Royal Artillery, have inventedImprovements in Ordnance; and I do hereby declare that the following isa full and exact description thereof'. f

The inside ot' a tube being more stretched by pressure from within thanthe. middle and outside, in about the ratio of the squares ofthediameters ot1 the layers, I patented in Great Britain, in February,1855, a method of obtaining increased strength in ordnance by build ingcannon ot' two or more concentric tubes, of which the outer compresstheinner to a definite degree, so that on the gun being tired all theconcentric tubes act together in resisting the strain. This method hasbeen much used, particularly in America, by Mr. Parrott. Another methodot increasing the strength of cannon has been used by the Dutch, andproposed in England by Captain Palliser. It consists in placing a veryyielding materialsuch as bronze or wroughtiron-inside of cast-iron,Without any compression of the iuner tubes or extension of the outer.Ihis latV ter plan is not applicable for large ordnance of great power,because metals cannot be found possessing both suiiicient difference otextensibility and at the same time the other qualities required forordnance. I therefore make cannon in the following manner: .l build thegun of concentric tubes, the inner tube being of a material that is mostextensible within the elastic limit, the next tube less extensiblewithin the elasticlimit, and so on, decreasing in extensibility withinthe elastic limit to the outside. I do not, however, merely tit thetubes'together, but I but on each successive layer with so much initialtension that the whole 'shall be worked by pressure from Within to,about the same degree-that is to say, the initial tension ofthesuccessive tubes shall compensate for an y deciency in the extensibilityofthe tubes within them, so that all the tubes shall contribute' equallyof their strengtho resist pressure from within. I prefer that nopartshall be stretched more ythan two-fifths as much as would cansepermanent sensible enlargement. Hard steel is a suitable material forthe outer parts and mild steel for the inner. However, I tind itconvenient sometimes to use wroughtiron, bronze, or soft steel or steelhardened in oil t'or the inside, and various qualities of cast iron forthe center and outside parts; or sometimes I use cast-iron for thecenter part orl cesses of hardening and annealing, &c. The

strengthening is 'not necessar t the whole length of the gun.

The accompanying drawing is a section ot' a four and three fourths inchgun [have made. A is a tube of mild steel, surrounded by B, a tube ot'harder steel, over so much of its length as is necessary to resist thepressure of the gas of the gunpowder where great. Before being put on,the inner diameter ot' B was about one two hundredths part ot' an inchless than the outer diameter of A, because the inside of B could stretchwithout risk ci' injury so much more than the outside of A would be.stretched when the inside of A was extended so far as consistent withpert'eet safety.

I claim- The manufacture of cannon composed ot' two or more tubes havingsuccessively-decreasing amounts ot' extensibility within the extensiblelimit, (the inner tube having the greatest amount,) when these tubes areput together with initial tension, substantially in the manner and forthe purpose described.

T. A. BLAKELY.

Witnesses It. A. BROOMAN, I. C. MEWBURN,

Both of 166 Fleet Street, London.

